APR-246 reactivates mutant p53 by targeting cysteines 124 and 277. Cell Death Dis. 2018;9:439. [PMID: 29670092 PMCID: PMC5906465 DOI: 10.1038/s41419-018-0463-7]

Targeting anti-apoptotic mechanisms in tumour cells: Strategies for enhancing Cancer therapy

Anti-cancer drug's cytotoxicity is determined by their ability to induce predetermined cell demise, commonly called apoptosis. The cancer-causing cells are able to evade cell death, which has been affiliated with both malignancy as well as resistance to cancer treatments. In order to avoid cell death, cancerous tumour cells often produce an abundance of anti-apoptotic proteins, becoming "dependent" on them. Consequently, protein inhibitors of cell death may prove to be beneficial as pharmacological targets for the future creation of cancer therapies. This article examines the molecular routes of apoptosis, its clinical manifestations, anti-cancer therapy options that target the intrinsic mechanism of apoptosis, proteins that prevent cell death, and members of the B-lymphoma-2 subset. In addition, novel approaches to cell death are highlighted, including how curcumin mitigates chemotherapy-induced apoptosis in healthy tissues and the various ways melatonin modifies apoptosis to improve cancer treatment efficacy, particularly through the TNF superfamily. Cancer treatment-induced increases in anti-apoptotic proteins lead to drug resistance; yet, ligands that trigger cell death by inhibiting these proteins are expected to improve chemotherapy's efficacy. The potential of frequency-modulated dietary phytochemicals as a cancer therapeutic pathway, including autophagy and apoptosis, is also explored. This approach may be more efficient than inhibition alone in overcoming drug resistance. Consequently, this method has the potential to allow for lower medication concentrations, reducing cytotoxicity and unwanted side effects.

Strategies for Anticancer Treatment in p53-Mutated Head and Neck Squamous Cell Carcinoma

This Opinion summarizes the strategies for anticancer treatment in p53-mutated head and neck squamous cell carcinoma (HNSCC). It examines six strategies for anticancer treatment in p53-mutated HNSCC: 1. direct reactivation of mutated p53; 2. activation of p63; 3. activation of p73; 4. degradation of mutated p53; 5. blocking the p53-regulated oncogenic microRNA; and 6. blocking the p53-regulated oncogenic long non-coding RNA. Since HNSCC has a high p53 mutation rate compared to other types of cancers, these strategies for combating p53-mutated HNSCC may prove useful for generating new ideas or methods for developing treatments for other cancers with p53 mutations. This article also explores other factors that may impact the effectiveness of anticancer therapies in p53-mutated HNSCC.

Pharmacological Modulation of Mutant TP53 with Oncotargets Against Esophageal Cancer and Therapy Resistance

The prevalence and deaths from esophageal cancer (EC) have recently increased. Although therapeutic strategies depend on the EC stage and recurrence, such as surgical intervention, chemotherapy, radiation therapy, chemoradiation therapy, targeted therapy, and immunotherapy, a more effective and novel treatment for EC is still required. This review briefly describes and summarizes some insightful oncotargets involved in the metabolic modulation of EC, including (1) cancer stem cells (CSCs) for EC progression, poor prognosis, tumor recurrence, and therapy resistance; (2) retinoic acid receptors (RARs) for esophageal carcinogenesis and regeneration; (3) phosphofructokinase (PFK) for EC-reprogrammed glycolysis; (4) lactate dehydrogenase (LDH) as an EC peripheral blood biomarker; and (5) hypoxia-inducible factor-1 alpha (HIF-1α) for the tumor microenvironment under hypoxic conditions. Moreover, the aforementioned oncotargets can be modulated by mutant TP53 and have their own features in the carcinogenesis, differentiation, proliferation, and metastasis of EC. Thus, the clarification of pharmacological mechanisms regarding the interaction between mutant TP53 and the abovementioned oncotargets could provide precise and perspective opinions for minimizing prediction errors, reducing therapy resistance, and developing novel drugs against EC.

Deciphering the safeguarding role of cysteine residues in p53 against H2O2-induced oxidation using high-resolution native mass spectrometry

The transcription factor p53 is exquisitely sensitive and selective to a broad variety of cellular environments. Several studies have reported that oxidative stress weakens the p53-DNA binding affinity for certain promoters depending on the oxidation mechanism. Despite this body of work, the precise mechanisms by which the physiologically relevant DNA-p53 tetramer complex senses cellular stresses caused by H2O2 are still unknown. Here, we employed native mass spectrometry (MS) and ion mobility (IM)-MS coupled to chemical labelling and H2O2-induced oxidation to examine the mechanism of redox regulation of the p53-p21 complex. Our approach has found that two reactive cysteines in p53 protect against H2O2-induced oxidation by forming reversible sulfenates.

Elucidating the immune landscape and potential prognostic model in acute myeloid leukemia with TP53 mutation

OBJECTIVES

The TP53 mutation, a prevalent tumor suppressor gene alteration, is linked to chemotherapy resistance, increased relapse rates and diminished overall survival (OS) in acute myeloid leukemia (AML) patients.

METHODS

In this study, we characterize the TP53 mutation phenotypes across various AML cohorts utilizing The Cancer Genome Atlas (TCGA) data. We devised a TP53-related prognostic signature derived from differentially expressed genes between mutated and wild-type TP53 AML specimens. In-depth analyses were conducted, encompassing genetic variation, immune cell infiltration and prognostic stratification.

RESULTS

A six-gene TP53-related signature was established using least absolute shrinkage and selection operator (LASSO)-Cox regression, demonstrating robust prognostic predictability. This signature exhibited strong performance in both the OHSU validation cohorts, an independent Gene Expression Omnibus (GEO) validation cohort (GSE71014) and proved by results of the in vivo experiment. Finally, we used single cell database (GSE198681) to observe the characteristics of these six genes.

DISCUSSION

Our study may facilitate the development of efficacious therapeutic approaches and provide a novel idea for future research. Conclusion: The TP53-related signature and pattern hold the potential to refine prognostic stratification and underscore emerging targeted therapies.

Tryptophanol-derived oxazoloisoindolinone fluorescent probes for cellular localization studies of p53 activators

The protein p53 is a transcription factor with several key roles in cells, including acting as a tumour suppressor. In most human cancers its tumour suppressor function is inactivated, either through inhibition by negative regulators or by mutation in the TP53 gene. Thus, there is a high interest in developing molecules able to activate p53 tumour suppressor activity. Tryptophanol-derived isoindolinones are known to act as wild-type and mutant p53 activators. Specifically, SLMP53-1 is a non-fluorescent wild-type and mutant p53 R280K reactivator, with potent in vivo anti-tumour activity in HCT116 and MDA-MB-231 mice xenograft models. With the aim of studying tryptophanol-derived isoindolinones intracellular localization by fluorescence microscopy, three SLMP53-1 based fluorescent probes were prepared. Here we report the design, synthesis, photophysical characterization, antiproliferative activity and cell localization studies of these fluorescent probes. The previously described structure-activity relationships of the SLMP53-1 scaffold set the basis for the design the fluorescent probes. The probes were prepared by connecting a small fluorophore (dansyl or 7-nitrobenzofurazan) to the indole nitrogen of the tryptophanol-derived oxazoloisoindolinone SLMP53-1 through two different linkers. The antiproliferative activity and cell localization studies of the three fluorescent probes were performed in HCT116 cells. The three probes showed enhanced internalization when compared with their fluorophore-linker intermediates, good photo-stability and high affinity for the endoplasmic reticulum, indicating the potential involvement of endoplasmic reticulum in the mechanism of action of tryptophanol-derived oxazoloisoindolinones.

EZHIP's role in diffuse midline glioma: echoes of oncohistones?

The enhancer of zeste inhibitory protein (EZHIP) is typically expressed during germ cell development and has been classified as a cancer-testis antigen (CTA) in various cancers. In 2020, 4% of diffuse midline gliomas (DMGs) were shown to aberrantly express EZHIP, mirroring the DMG hallmark histone H3 K27M (H3K27M) oncohistone mutation. Similar to H3K27M, EZHIP is a negative regulator of polycomb repressive complex 2 (PRC2), leading to global epigenomic remodeling. In this opinion, we explore the similarities and disparities between H3K27M- and EZHIP-DMGs with a focus on their shared functional hallmark of PRC2 inhibition, their genetic and epigenomic landscapes, plausible differences in the cell of origin, and therapeutic avenues. Upcoming research on EZHIP will help better understand its role in gliomagenesis and DMG therapy.

From regulation to deregulation of p53 in hematologic malignancies: implications for diagnosis, prognosis and therapy

The p53 protein, encoded by the TP53 gene, serves as a critical tumor suppressor, playing a vital role in maintaining genomic stability and regulating cellular responses to stress. Dysregulation of p53 is frequently observed in hematological malignancies, significantly impacting disease progression and patient outcomes. This review aims to examine the regulatory mechanisms of p53, the implications of TP53 mutations in various hematological cancers, and emerging therapeutic strategies targeting p53. We conducted a comprehensive literature review to synthesize recent findings related to p53's multifaceted role in hematologic cancers, focusing on its regulatory pathways and therapeutic potential. TP53 mutations in hematological malignancies often lead to treatment resistance and poor prognosis. Current therapeutic strategies, including p53 reactivation and gene therapy, show promise in improving treatment outcomes. Understanding the intricacies of p53 regulation and the consequences of its mutations is essential for developing effective diagnostic and therapeutic strategies in hematological malignancies, ultimately enhancing patient care and survival.

Covalent Modification of p53 by (E)-1-(4-Methylpiperazin-1-yl)-3-(5-nitrofuran-2-yl)prop-2-en-1-one

TP53 is commonly mutated in cancer, giving rise to loss of wild-type tumor suppressor function and increases in gain-of-function oncogenic roles. Thus, inhibition of mutant p53 and reactivation of wild-type function represents a potential means to target diverse tumor types. (E)-1-(4-Methylpiperazin-1-yl)-3-(5-nitrofuran-2-yl)prop-2-en-1-one (NSC59984), first identified from a high-throughput screen, induces wild-type p53 signaling and antiproliferative effects while inhibiting mutant p53 gain-of-function activities. Here, we investigate the specific mechanism of action of NSC59984 against p53. We found that NSC59984 reacts with thiols via an unusual Michael addition at the α-carbon. Covalent modification of p53 Cys124 and Cys229 was observed both following in vitro reaction and upon treatment of cells. Finally, we used a biotinylated form of NSC59984 and, separately, thermal proteome profiling to examine off-target effects, identifying several metabolic proteins involved in cellular metabolism as potential targets. These results demonstrate that covalent modification of p53 by NSC59984 leads to increased wild-type activity and suggest that potential reaction with metabolic enzymes may contribute to antiproliferative function.

Phase separation in DNA damage response: New insights into cancer development and therapy

Phase separation, a process in which biomolecules segregate into distinct liquid-like compartments within cells, has recently been identified as a crucial regulator of various cellular functions, including the DNA damage response (DDR). Dysregulation of phase separation may contribute to genomic instability, oncogenesis, and tumor progression. However, the specific roles and mechanisms underlying phase separation remain largely elusive. This comprehensive review aims to elucidate the complex relationship between phase separation and the DDR in the context of cancer biology. We focus on the molecular mechanisms underlying phase separation and its role in orchestrating DDR signaling and repair processes. Additionally, we discuss how the dysregulation of phase separation in cancer cells impacts genome stability, tumorigenesis, and therapeutic responses. By leveraging the unique properties of phase separation in the DDR, researchers can potentially advance basic research and develop personalized cancer therapies targeting the dysregulated biomolecular condensates that drive tumorigenesis.

Novel dual-pathogen multi-epitope mRNA vaccine development for Brucella melitensis and Mycobacterium tuberculosis in silico approach

Brucellosis and Tuberculosis, both of which are contagious diseases, have presented significant challenges to global public health security in recent years. Delayed treatment can exacerbate the conditions, jeopardizing patient lives. Currently, no vaccine has been approved to prevent these two diseases simultaneously. In contrast to traditional vaccines, mRNA vaccines offer advantages such as high efficacy, rapid development, and low cost, and their applications are gradually expanding. This study aims to develop multi-epitope mRNA vaccines argeting Brucella melitensis and Mycobacterium tuberculosis H37Rv (L4 strain) utilizing immunoinformatics approaches. The proteins Omp25, Omp31, MPT70, and MPT83 from the specified bacteria were selected to identify the predominant T- and B-cell epitopes for immunological analysis. Following a comprehensive evaluation, a vaccine was developed using helper T lymphocyte epitopes, cytotoxic T lymphocyte epitopes, linear B-cell epitopes, and conformational B-cell epitopes. It has been demonstrated that multi-epitope mRNA vaccines exhibit increased antigenicity, non-allergenicity, solubility, and high stability. The findings from molecular docking and molecular dynamics simulation revealed a robust and enduring binding affinity between multi-epitope peptides mRNA vaccines and TLR4. Ultimately, Subsequently, following the optimization of the nucleotide sequence, the codon adaptation index was calculated to be 1.0, along with an average GC content of 54.01%. This indicates that the multi-epitope mRNA vaccines exhibit potential for efficient expression within the Escherichia coli(E. coli) host. Analysis through immune modeling indicates that following administration of the vaccine, there may be variation in immunecell populations associated with both innate and adaptive immune reactions. These types encompass helper T lymphocytes (HTL), cytotoxic T lymphocytes (CTL), regulatory T lymphocytes, natural killer cells, dendritic cells and various immune cell subsets. In summary, the results suggest that the newly created multi-epitope mRNA vaccine exhibits favorable attributes, offering novel insights and a conceptual foundation for potential progress in vaccine development.

Integrated stress response (ISR) activation and apoptosis through HRI kinase by PG3 and other p53 pathway-restoring cancer therapeutics

Restoration of the p53 pathway has been a long-term goal in the field of cancer research to treat tumors with mutated p53 and aggressive clinical behavior. p53 pathway restoration in p53-deficient cancers can be achieved by small molecules via p53-dependent or p53-independent processes. Hereafter p53-independent restoration of p53-pathway-signaling in p53-deficient/mutated tumors is referred to as 'restoration of the p53 pathway'. We compare activation of p53 target genes by novel compounds PG3 and PG3-Oc, that activate p53-target genes in a p53-independent manner, and four mutant p53-activating compounds while Nutlin-3a is used as negative control. PG3 and PG3-Oc upregulate p21, PUMA, and DR5 in five cancer cell lines with various p53 mutational statuses through ATF4 (Activating Transcriptional Factor 4) and integrated stress response (ISR) independent of p53. Mutant p53-targeting compounds induce expression of the 3 major downstream p53 target genes and ATF4 in a highly variable and cell-type-dependent manner. PG3 treatment activates ATF4 through ISR via kinase HRI (Heme-Regulated Inhibitor). ATF4 mediates upregulation of PUMA, p21, and NAG-1/GDF15 (Nonsteroidal anti-inflammatory drug-activated gene 1). We note that PUMA mediates apoptosis through activation of caspase-8 in HT29 cells and potentially caspase-10 in SW480 cells. We provide a novel mechanism engaged by PG3 to induce cell death via the HRI/ATF4/PUMA axis. Our results provide unique insights into the mechanism of action of PG3 as a novel cancer therapeutic targeting p53 pathway-like tumor suppression.

Common Driver Mutations in AML: Biological Impact, Clinical Considerations, and Treatment Strategies

Next-generation sequencing of samples from patients with acute myeloid leukemia (AML) has revealed several driver gene mutations in adult AML. However, unlike other cancers, AML is defined by relatively few mutations per patient, with a median of 4-5 depending on subtype. In this review, we will discuss the most common driver genes found in patients with AML and focus on the most clinically relevant ones that impact treatment strategies. The most common driver gene mutations in AML occur in NPM1 and FLT3, accounting for ~30% each. There are now targeted therapies being tested or already approved for these driver genes. Menin inhibitors, a novel targeted therapy that blocks the function of the menin protein, are in clinical trials for NPM1 driver gene mutant AML after relapse. A number of FLT3 inhibitors are now approved for FLT3 driver gene mutant AML in combination with chemotherapy in the frontline and also as single agent in relapse. Although mutations in IDH1/2 and TP53 only occur in around 10-20% of patients with AML each, they can affect the treatment strategy due to their association with prognosis and availability of targeted agents. While the impact of other driver gene mutations in AML is recognized, there is a lack of data on the actionable impact of those mutations.

Pyrimidine Triones as Potential Activators of p53 Mutants

p53 is a crucial tumor suppressor in vertebrates that is frequently mutated in human cancers. Most mutations are missense mutations that render p53 inactive in suppressing tumor initiation and progression. Developing small-molecule drugs to convert mutant p53 into an active, wild-type-like conformation is a significant focus for personalized cancer therapy. Prior research indicates that reactivating p53 suppresses cancer cell proliferation and tumor growth in animal models. Early clinical evidence with a compound selectively targeting p53 mutants with substitutions of tyrosine 220 suggests potential therapeutic benefits of reactivating p53 in patients. This study identifies and examines the UCI-1001 compound series as a potential corrector for several p53 mutations. The findings indicate that UCI-1001 treatment in p53 mutant cancer cell lines inhibits growth and reinstates wild-type p53 activities, including DNA binding, target gene activation, and induction of cell death. Cellular thermal shift assays, conformation-specific immunofluorescence staining, and differential scanning fluorometry suggest that UCI-1001 interacts with and alters the conformation of mutant p53 in cancer cells. These initial results identify pyrimidine trione derivatives of the UCI-1001 series as candidates for p53 corrector drug development.

An engineered DNA aptamer-based PROTAC for precise therapy of p53-R175H hotspot mutant-driven cancer

Targeting oncogenic mutant p53 represents an attractive strategy for cancer treatment due to the high frequency of gain-of-function mutations and ectopic expression in various cancer types. Despite extensive efforts, the absence of a druggable active site for small molecules has rendered these mutants therapeutically non-actionable. Here we develop a selective and effective proteolysis-targeting chimera (PROTAC) for p53-R175H, a common hotspot mutant with dominant-negative and oncogenic activity. Using a novel iterative molecular docking-guided post-SELEX (systematic evolution of ligands by exponential enrichment) approach, we rationally engineer a high-performance DNA aptamer with improved affinity and specificity for p53-R175H. Leveraging this resulting aptamer as a binder for PROTACs, we successfully developed a selective p53-R175H degrader, named dp53m. dp53m induces the ubiquitin-proteasome-dependent degradation of p53-R175H while sparing wildtype p53. Importantly, dp53m demonstrates significant antitumor efficacy in p53-R175H-driven cancer cells both in vitro and in vivo, without toxicity. Moreover, dp53m significantly and synergistically improves the sensitivity of these cells to cisplatin, a commonly used chemotherapy drug. These findings provide evidence of the potential therapeutic value of dp53m in p53-R175H-driven cancers.

Targeting apoptotic pathways for cancer therapy

Apoptosis is a form of programmed cell death that is mediated by intrinsic and extrinsic pathways. Dysregulation of and resistance to cell death are hallmarks of cancer. For over three decades, the development of therapies to promote treatment of cancer by inducing various cell death modalities, including apoptosis, has been a main goal of clinical oncology. Apoptosis pathways also interact with other signaling mechanisms, such as the p53 signaling pathway and the integrated stress response (ISR) pathway. In addition to agents directly targeting the intrinsic and extrinsic pathway components, anticancer drugs that target the p53 and ISR signaling pathways are actively being developed. In this Review, we discuss selected and promising anticancer therapies in various stages of development, including drug targets, mechanisms, and resistance to related treatments, focusing especially on B cell lymphoma 2 (BCL-2) inhibitors, TRAIL analogues, DR5 antibodies, and strategies that target p53, mutant p53, and the ISR.

p53 at the crossroads of tumor immunity

The p53 tumor suppressor protein has a plethora of cell-intrinsic functions and consequences that impact diverse cell types and tissues. Recent studies are beginning to unravel how wild-type and mutant p53 work in distinct ways to modulate tumor immunity. This sets up a disequilibrium between tumor immunosurveillance and escape therefrom. The ability to exploit this emerging knowledge for translational approaches may shape immunotherapy and targeted therapeutics in the future, especially in combinatorial settings.

Evaluation of a Covalent Library of Diverse Warheads (CovLib) Binding to JNK3, USP7, or p53

Purpose

Over the last few years, covalent fragment-based drug discovery has gained significant importance. Thus, striving for more warhead diversity, we conceived a library consisting of 20 covalently reacting compounds. Our covalent fragment library (CovLib) contains four different warhead classes, including five α-cyanoacacrylamides/acrylates (CA), three epoxides (EO), four vinyl sulfones (VS), and eight electron-deficient heteroarenes with a leaving group (SNAr/SN).

Methods

After predicting the theoretical solubility of the fragments by LogP and LogS during the selection process, we determined their experimental solubility using a turbidimetric solubility assay. The reactivities of the different compounds were measured in a high-throughput 5,5'-dithiobis-(2-nitrobenzoic acid) DTNB assay, followed by a (glutathione) GSH stability assay. We employed the CovLib in a (differential scanning fluorimetry) DSF-based screening against different targets: c-Jun N-terminal kinase 3 (JNK3), ubiquitin-specific protease 7 (USP7), and the tumor suppressor p53. Finally, the covalent binding was confirmed by intact protein mass spectrometry (MS).

Results

In general, the purchased fragments turned out to be sufficiently soluble. Additionally, they covered a broad spectrum of reactivity. All investigated α-cyanoacrylamides/acrylates and all structurally confirmed epoxides turned out to be less reactive compounds, possibly due to steric hindrance and reversibility (for α-cyanoacrylamides/acrylates). The SNAr and vinyl sulfone fragments are either highly reactive or stable. DSF measurements with the different targets JNK3, USP7, and p53 identified reactive fragment hits causing a shift in the melting temperatures of the proteins. MS confirmed the covalent binding mode of all these fragments to USP7 and p53, while additionally identifying the SNAr-type electrophile SN002 as a mildly reactive covalent hit for p53.

Conclusion

The screening and target evaluation of the CovLib revealed first interesting hits. The highly cysteine-reactive fragments VS004, SN001, SN006, and SN007 covalently modify several target proteins and showed distinct shifts in the melting temperatures up to +5.1 °C and -9.1 °C.

Assessment and process optimization of high throughput biofabrication of immunocompetent breast cancer model for drug screening applications

Recent advancements in 3D cancer modeling have significantly enhanced our ability to delve into the intricacies of carcinogenesis. Despite the pharmaceutical industry's substantial investment of both capital and time in the drug screening and development pipeline, a concerning trend persists: drug candidates screened on conventional cancer models exhibit a dismal success rate in clinical trials. One pivotal factor contributing to this discrepancy is the absence of drug testing on pathophysiologically biomimetic 3D cancer models during pre-clinical stages. Unfortunately, current manual methods of 3D cancer modeling, such as spheroids and organoids, suffer from limitations in reproducibility and scalability. In our study, we have meticulously developed 3D bioprinted breast cancer model utilizing decellularized adipose tissue-based hydrogel obtained via a detergent-free decellularization method. Our innovative printing techniques allows for rapid, high-throughput fabrication of 3D cancer models in a 96-well plate format, demonstrating unmatched scalability and reproducibility. Moreover, we have conducted extensive validation, showcasing the efficacy of our platform through drug screening assays involving two potent anti-cancer drugs, 5-Fluorouracil and PRIMA-1Met. Notably, our platform facilitates effortless imaging and gene expression analysis, streamlining the evaluation process. In a bid to enhance the relevance of our cancer model, we have introduced a heterogeneous cell population into the DAT-based bioink. Through meticulous optimization and characterization, we have successfully developed a biomimetic immunocompetent breast cancer model, complete with microenvironmental cues and diverse cell populations. This breakthrough paves the way for rapid multiplex drug screening and the development of personalized cancer models, marking a paradigm shift in cancer research and pharmaceutical development.

Oncogenes and tumor suppressor genes: functions and roles in cancers

Cancer, being the most formidable ailment, has had a profound impact on the human health. The disease is primarily associated with genetic mutations that impact oncogenes and tumor suppressor genes (TSGs). Recently, growing evidence have shown that X-linked TSGs have specific role in cancer progression and metastasis as well. Interestingly, our genome harbors around substantial portion of genes that function as tumor suppressors, and the X chromosome alone harbors a considerable number of TSGs. The scenario becomes even more compelling as X-linked TSGs are adaptive to key epigenetic processes such as X chromosome inactivation. Therefore, delineating the new paradigm related to X-linked TSGs, for instance, their crosstalk with autosome and involvement in cancer initiation, progression, and metastasis becomes utmost importance. Considering this, herein, we present a comprehensive discussion of X-linked TSG dysregulation in various cancers as a consequence of genetic variations and epigenetic alterations. In addition, the dynamic role of X-linked TSGs in sex chromosome-autosome crosstalk in cancer genome remodeling is being explored thoroughly. Besides, the functional roles of ncRNAs, role of X-linked TSG in immunomodulation and in gender-based cancer disparities has also been highlighted. Overall, the focal idea of the present article is to recapitulate the findings on X-linked TSG regulation in the cancer landscape and to redefine their role toward improving cancer treatment strategies.

Unveiling the Mechanisms of EGCG-p53 Interactions through Molecular Dynamics Simulations

Green tea consumption is associated with protective and preventive effects against various types of cancer. These effects are attributed to polyphenols, particularly epigallocatechin-3-gallate (EGCG). EGCG acts by directly inhibiting tumor suppressor protein p53. The binding mechanism by which EGCG inhibits p53 activity is associated with residues Trp23-Lys24 and Pro47-Thr55 within the p53 N-terminal domain (NTD). However, the structural and thermodynamic aspects of the interaction between EGCG and p53 are poorly understood. Therefore, based on crystallographic data, we combine docking, molecular dynamics (MD) simulations, and molecular mechanics generalized Born surface area approaches to explore the intricacies of the EGCG-p53 binding mechanism. A triplicate microsecond MD simulation for each system is initially performed to capture diverse p53 NTD conformations. From the start, the most populated cluster of the second run (R2-1) stands out due to a unique opening between Trp23 and Trp53. During MD simulations, this conformation allows EGCG to sustain a high level of stability and affinity while interacting with both regions of interest and deepening the binding pocket. Structural analysis emphasizes the significance of pyrogallol motifs in EGCG binding. Therefore, the conformational shift in this gap is pivotal, enabling EGCG to impede p53 interactions and manifest its anticancer properties. These findings enhance the present comprehension of the anticancer properties of green tea polyphenols and pave the way for future therapeutic developments.

p53 biology and reactivation for improved therapy in MDS and AML

Myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) originate from preleukemic hematopoietic conditions, such as clonal hematopoiesis of indeterminate potential (CHIP) or clonal cytopenia of undetermined significance (CCUS) and have variable outcomes despite the successful implementation of targeted therapies. The prognosis differs depending on the molecular subgroup. In patients with TP53 mutations, the most inferior outcomes across independent studies were observed. Myeloid malignancies with TP53 mutations have complex cytogenetics and extensive structural variants. These factors contribute to worse responses to induction therapy, demethylating agents, or venetoclax-based treatments. Survival of patients with biallelic TP53 gene mutations is often less than one year but this depends on the type of treatment applied. It is still controversial whether the allelic state of mutant TP53 impacts the outcomes in patients with AML and high-risk MDS. Further studies are needed to justify estimating TP53 LOH status for better risk assessment. Yet, TP53-mutated MDS, MDS/AML and AML are now classified separately in the International Consensus Classification (ICC). In the clinical setting, the wild-type p53 protein is reactivated pharmacologically by targeting p53/MDM2/MDM4 interactions and mutant p53 reactivation is achieved by refolding the DNA binding domain to wild-type-like conformation or via targeted degradation of the mutated protein. This review discusses our current understanding of p53 biology in MDS and AML and the promises and failures of wild-type and mutant p53 reactivation in the clinical trial setting.

Characterization of the generic mutant p53-rescue compounds in a broad range of assays

Dozens of compounds that rescue tumor-associated mutant p53 have been reported. Xiao et al. perform 10 assays to evaluate effectiveness of the mutant p53-rescue compounds side-by-side but do not detect reliable rescue in any assay for the evaluated compounds, except for ATO and its analog PAT.

Translating p53-based therapies for cancer into the clinic

Inactivation of the most important tumour suppressor gene TP53 occurs in most, if not all, human cancers. Loss of functional wild-type p53 is achieved via two main mechanisms: mutation of the gene leading to an absence of tumour suppressor activity and, in some cases, gain-of-oncogenic function; or inhibition of the wild-type p53 protein mediated by overexpression of its negative regulators MDM2 and MDMX. Because of its high potency as a tumour suppressor and the dependence of at least some established tumours on its inactivation, p53 appears to be a highly attractive target for the development of new anticancer drugs. However, p53 is a transcription factor and therefore has long been considered undruggable. Nevertheless, several innovative strategies have been pursued for targeting dysfunctional p53 for cancer treatment. In mutant p53-expressing tumours, the predominant strategy is to restore tumour suppressor function with compounds acting either in a generic manner or otherwise selective for one or a few specific p53 mutations. In addition, approaches to deplete mutant p53 or to target vulnerabilities created by mutant p53 expression are currently under development. In wild-type p53 tumours, the major approach is to protect p53 from the actions of MDM2 and MDMX by targeting these negative regulators with inhibitors. Although the results of at least some clinical trials of MDM2 inhibitors and mutant p53-restoring compounds are promising, none of the agents has yet been approved by the FDA. Alternative strategies, based on a better understanding of p53 biology, the mechanisms of action of compounds and treatment regimens as well as the development of new technologies are gaining interest, such as proteolysis-targeting chimeras for MDM2 degradation. Other approaches are taking advantage of the progress made in immune-based therapies for cancer. In this Review, we present these ongoing clinical trials and emerging approaches to re-evaluate the current state of knowledge of p53-based therapies for cancer.

Cell fate regulation governed by p53: Friends or reversible foes in cancer therapy

Cancer is a leading cause of death worldwide. Targeted therapies aimed at key oncogenic driver mutations in combination with chemotherapy and radiotherapy as well as immunotherapy have benefited cancer patients considerably. Tumor protein p53 (TP53), a crucial tumor suppressor gene encoding p53, regulates numerous downstream genes and cellular phenotypes in response to various stressors. The affected genes are involved in diverse processes, including cell cycle arrest, DNA repair, cellular senescence, metabolic homeostasis, apoptosis, and autophagy. However, accumulating recent studies have continued to reveal novel and unexpected functions of p53 in governing the fate of tumors, for example, functions in ferroptosis, immunity, the tumor microenvironment and microbiome metabolism. Among the possibilities, the evolutionary plasticity of p53 is the most controversial, partially due to the dizzying array of biological functions that have been attributed to different regulatory mechanisms of p53 signaling. Nearly 40 years after its discovery, this key tumor suppressor remains somewhat enigmatic. The intricate and diverse functions of p53 in regulating cell fate during cancer treatment are only the tip of the iceberg with respect to its equally complicated structural biology, which has been painstakingly revealed. Additionally, TP53 mutation is one of the most significant genetic alterations in cancer, contributing to rapid cancer cell growth and tumor progression. Here, we summarized recent advances that implicate altered p53 in modulating the response to various cancer therapies, including chemotherapy, radiotherapy, and immunotherapy. Furthermore, we also discussed potential strategies for targeting p53 as a therapeutic option for cancer.

Understanding the prion-like behavior of mutant p53 proteins in triple-negative breast cancer pathogenesis: The current therapeutic strategies and future directions

Breast cancer (BC) is viewed as a significant public health issue and is the primary cause of cancer-related deaths among women worldwide. Triple-negative breast cancer (TNBC) is a particularly aggressive subtype that predominantly affects young premenopausal women. The tumor suppressor p53 playsa vital role in the cellular response to DNA damage, and its loss or mutations are commonly present in many cancers, including BC. Recent evidence suggests that mutant p53 proteins can aggregate and form prion-like structures, which may contribute to the pathogenesis of different types of malignancies, such as BC. This review provides an overview of BC molecular subtypes, the epidemiology of TNBC, and the role of p53 in BC development. We also discuss the potential implications of prion-like aggregation in BC and highlight future research directions. Moreover, a comprehensive analysis of the current therapeutic approaches targeting p53 aggregates in BC treatment is presented. Strategies including small molecules, chaperone inhibitors, immunotherapy, CRISPR-Cas9, and siRNA are discussed, along with their potential benefits and drawbacks. The use of these approaches to inhibit p53 aggregation and degradation represents a promising target for cancer therapy. Future investigations into the efficacy of these approaches against various p53 mutations or binding to non-p53 proteins should be conducted to develop more effective and personalized therapies for BC treatment.

Unmet Horizons: Assessing the Challenges in the Treatment of TP53-Mutated Acute Myeloid Leukemia

Acute myeloid leukemia (AML) remains a challenging hematologic malignancy. The presence of TP53 mutations in AML poses a therapeutic challenge, considering that standard treatments face significant setbacks in achieving meaningful responses. There is a pressing need for the development of innovative treatment modalities to overcome resistance to conventional treatments attributable to the unique biology of TP53-mutated (TP53mut) AML. This review underscores the role of TP53 mutations in AML, examines the current landscape of treatment options, and highlights novel therapeutic approaches, including targeted therapies, combination regimens, and emerging immunotherapies, as well as agents being explored in preclinical studies according to their potential to address the unique hurdles posed by TP53mut AML.

Therapeutic biomarkers in acute myeloid leukemia: functional and genomic approaches

Acute myeloid leukemia (AML) is clinically and genetically a heterogeneous disease characterized by clonal expansion of abnormal hematopoietic progenitors. Genomic approaches to precision medicine have been implemented to direct targeted therapy for subgroups of AML patients, for instance, IDH inhibitors for IDH1/2 mutated patients, and FLT3 inhibitors with FLT3 mutated patients. While next generation sequencing for genetic mutations has improved treatment outcomes, only a fraction of AML patients benefit due to the low prevalence of actionable targets. In recent years, the adoption of newer functional technologies for quantitative phenotypic analysis and patient-derived avatar models has strengthened the potential for generalized functional precision medicine approach. However, functional approach requires robust standardization for multiple variables such as functional parameters, time of drug exposure and drug concentration for making in vitro predictions. In this review, we first summarize genomic and functional therapeutic biomarkers adopted for AML therapy, followed by challenges associated with these approaches, and finally, the future strategies to enhance the implementation of precision medicine.

An overview of the functions of p53 and drugs acting either on wild- or mutant-type p53

TP53, also known as the "guardian of the genome," is an important tumor suppressor gene. It is encoded by the human genome and is associated with the development of diverse cancers. The p53 protein, encoded by TP53, functions in the cell to monitor DNA damage and prompts the cell to respond appropriately. When DNA is damaged, p53 halts the cell cycle, allowing cells to enter the repair state. If the repair is ineffective, p53 induces cell death via apoptosis. This prevents DNA damage transmission during cell division and reduces cancer risk. However, the p53 gene mutation compromises its function. This leads to the inability of cells to respond properly to DNA damage, which may result in cancer development. Mutations in p53 are widespread in diverse cancers, especially highly prevalent cancers, including breast, colon, and lung cancers. Despite the association between p53 mutations and cancer, researchers have discovered drugs and treatments that may reactivate mutated p53 function. Therefore, p53 remains an important area of research in cancer treatment and holds promise as a new direction for cancer therapy. In summary, TP53 is a vital tumor suppressor gene responsible for monitoring DNA damage and prompting cells to respond appropriately. This article summarizes drugs related to p53 and diverse strategies for discovering drugs that act on either wide or mutant p53. Herein, p53 is categorized into two types: wild and mutant type. Drugs are also classified according to diverse treatment strategies, enabling readers to differentiate between the two types of p53 and aiding in selecting the appropriate research direction. Additionally, this review offers a valuable reference for drug design.

Pharmacological reactivation of p53 in the era of precision anticancer medicine

p53, which is encoded by the most frequently mutated gene in cancer, TP53, is an attractive target for novel cancer therapies. Despite major challenges associated with this approach, several compounds that either augment the activity of wild-type p53 or restore all, or some, of the wild-type functions to p53 mutants are currently being explored. In wild-type TP53 cancer cells, p53 function is often abrogated by overexpression of the negative regulator MDM2, and agents that disrupt p53-MDM2 binding can trigger a robust p53 response, albeit potentially with induction of p53 activity in non-malignant cells. In TP53-mutant cancer cells, compounds that promote the refolding of missense mutant p53 or the translational readthrough of nonsense mutant TP53 might elicit potent cell death. Some of these compounds have been, or are being, tested in clinical trials involving patients with various types of cancer. Nonetheless, no p53-targeting drug has so far been approved for clinical use. Advances in our understanding of p53 biology provide some clues as to the underlying reasons for the variable clinical activity of p53-restoring therapies seen thus far. In this Review, we discuss the intricate interactions between p53 and its cellular and microenvironmental contexts and factors that can influence p53's activity. We also propose several strategies for improving the clinical efficacy of these agents through the complex perspective of p53 functionality.

Potential applications of ferroptosis inducers and regulatory molecules in hematological malignancy therapy

Ferroptosis, a novel form of iron-dependent cell death, has emerged as a potential avenue for promoting tumor cell death by causing cell membrane rupture and the accumulation of lipid peroxides (LPO) in the cell. Since its discovery in 2012, extensive research has been conducted to explore the mechanism of ferroptosis inducers, including erastin, sulfasalazine, and sorafenib. These compounds inhibit system XC-, while Ras-selective lethal small molecule 3 (RSL3) and FION2 specifically target GPX4 to promote ferroptosis. Therefore, targeting ferroptosis presents a promising therapeutic approach for malignant tumors. While the study of ferroptosis in solid tumors has made significant progress, there is limited information available on its role in hematological tumors. This review aims to summarize the molecular mechanisms of ferroptosis inducers and discuss their clinical applications in hematological malignancies. Furthermore, the identification of non-coding RNAs (ncRNAs) and genes that regulate key molecules in the ferroptosis pathway could provide new targets and establish a molecular theoretical foundation for exploring novel ferroptosis inducers in hematological malignancies.

TP53 structure-function relationships in metastatic castrate-sensitive prostate cancer and the impact of APR-246 treatment

PURPOSE

Despite well-informed work in several malignancies, the phenotypic effects of TP53 mutations in metastatic castration-sensitive prostate cancer (mCSPC) progression and metastasis are not clear. We characterized the structure-function and clinical impact of TP53 mutations in mCSPC.

PATIENTS AND METHODS

We performed an international retrospective review of men with mCSPC who underwent next-generation sequencing and were stratified according to TP53 mutational status and metastatic burden. Clinical outcomes included radiographic progression-free survival (rPFS) and overall survival (OS) evaluated with Kaplan-Meier and multivariable Cox regression. We also utilized isogenic cancer cell lines to assess the effect of TP53 mutations and APR-246 treatment on migration, invasion, colony formation in vitro, and tumor growth in vivo. Preclinical experimental observations were compared using t-tests and ANOVA.

RESULTS

Dominant-negative (DN) TP53 mutations were enriched in patients with synchronous (vs. metachronous) (20.7% vs. 6.3%, p < 0.01) and polymetastatic (vs. oligometastatic) (14.4% vs. 7.9%, p < 0.01) disease. On multivariable analysis, DN mutations were associated with worse rPFS (hazards ratio [HR] = 1.97, 95% confidence interval [CI]: 1.31-2.98) and overall survival [OS] (HR = 2.05, 95% CI: 1.14-3.68) compared to TP53 wild type (WT). In vitro, 22Rv1 TP53 R175H cells possessed stronger migration, invasion, colony formation ability, and cellular movement pathway enrichment in RNA sequencing analysis compared to 22Rv1 TP53 WT cells. Treatment with APR-246 reversed the effects of TP53 mutations in vitro and inhibited 22Rv1 TP53 R175H tumor growth in vivo in a dosage-dependent manner.

CONCLUSIONS

DN TP53 mutations correlated with worse prognosis in prostate cancer patients and higher metastatic potential, which could be counteracted by APR-246 treatment suggesting a potential future therapeutic avenue.

Targeting apoptosis dysregulation in myeloid malignancies - The promise of a therapeutic revolution

In recent years, the therapeutic landscape of myeloid malignancies has been completely revolutionized by the introduction of several new drugs, targeting molecular alterations or pathways crucial for leukemia cells survival. Particularly, many agents targeting apoptosis have been investigated in both pre-clinical and clinical studies. For instance, venetoclax, a pro-apoptotic agent active on BCL-2 signaling, has been successfully used in the treatment of acute myeloid leukemia (AML). The impressive results achieved in this context have made the apoptotic pathway an attractive target also in other myeloid neoplasms, translating the experience of AML. Therefore, several drugs are now under investigation either as single or in combination strategies, due to their synergistic efficacy and capacity to overcome resistance. In this paper, we will review the mechanisms of apoptosis and the specific drugs currently used and under investigation for the treatment of myeloid neoplasia, identifying critical research necessities for the upcoming years.

Cellular senescence in glioma

INTRODUCTION

Glioma is the most common primary brain tumor and is often associated with treatment resistance and poor prognosis. Standard treatment typically involves radiotherapy and temozolomide-based chemotherapy, both of which induce cellular senescence-a tumor suppression mechanism.

DISCUSSION

Gliomas employ various mechanisms to bypass or escape senescence and remain in a proliferative state. Importantly, senescent cells remain viable and secrete a large number of factors collectively known as the senescence-associated secretory phenotype (SASP) that, paradoxically, also have pro-tumorigenic effects. Furthermore, senescent cells may represent one form of tumor dormancy and play a role in glioma recurrence and progression.

CONCLUSION

In this article, we delineate an overview of senescence in the context of gliomas, including the mechanisms that lead to senescence induction, bypass, and escape. Furthermore, we examine the role of senescent cells in the tumor microenvironment and their role in tumor progression and recurrence. Additionally, we highlight potential therapeutic opportunities for targeting senescence in glioma.

Targeting mutant p53 stabilization for cancer therapy

Over 50% cancer bears TP53 mutation, the highly stabilized mutant p53 protein drives the tumorigenesis and progression. Mutation of p53 not only cause loss-of-function and dominant-negative effects (DNE), but also results in the abnormal stability by the regulation of the ubiquitin-proteasome system and molecular chaperones that promote tumorigenesis through gain-of-function effects. The accumulation of mutant p53 is mainly regulated by molecular chaperones, including Hsp40, Hsp70, Hsp90 and other biomolecules such as TRIM21, BAG2 and Stat3. In addition, mutant p53 forms prion-like aggregates or complexes with other protein molecules and result in the accumulation of mutant p53 in tumor cells. Depleting mutant p53 has become one of the strategies to target mutant p53. This review will focus on the mechanism of mutant p53 stabilization and discuss how the strategies to manipulate these interconnected processes for cancer therapy.

Targeting Biomolecular Condensation and Protein Aggregation against Cancer

Biomolecular condensates, membrane-less entities arising from liquid-liquid phase separation, hold dichotomous roles in health and disease. Alongside their physiological functions, these condensates can transition to a solid phase, producing amyloid-like structures implicated in degenerative diseases and cancer. This review thoroughly examines the dual nature of biomolecular condensates, spotlighting their role in cancer, particularly concerning the p53 tumor suppressor. Given that over half of the malignant tumors possess mutations in the TP53 gene, this topic carries profound implications for future cancer treatment strategies. Notably, p53 not only misfolds but also forms biomolecular condensates and aggregates analogous to other protein-based amyloids, thus significantly influencing cancer progression through loss-of-function, negative dominance, and gain-of-function pathways. The exact molecular mechanisms underpinning the gain-of-function in mutant p53 remain elusive. However, cofactors like nucleic acids and glycosaminoglycans are known to be critical players in this intersection between diseases. Importantly, we reveal that molecules capable of inhibiting mutant p53 aggregation can curtail tumor proliferation and migration. Hence, targeting phase transitions to solid-like amorphous and amyloid-like states of mutant p53 offers a promising direction for innovative cancer diagnostics and therapeutics.

Treating accelerated and blast phase myeloproliferative neoplasms: progress and challenges

Myeloproliferative neoplasms (MPNs) are a group of clonal hematologic malignancies that include polycythemia vera (PV), essential thrombocythemia (ET), and myelofibrosis (MF). MPNs are characterized by activating mutations in the JAK/STAT pathway and an increased risk of transformation to an aggressive form of acute leukemia, termed MPN-blast phase (MPN-BP). MPN-BP is characterized by the presence of ⩾20% blasts in the blood or bone marrow and is almost always preceded by an accelerated phase (MPN-AP) defined as ⩾10-19% blasts in the blood or bone marrow. These advanced forms of disease are associated with poor prognosis with a median overall survival (mOS) of 3-5 months in MPN-BP and 13 months in MPN-AP. MPN-AP/BP has a unique molecular landscape characterized by increased intratumoral complexity. Standard therapies used in de novo acute myeloid leukemia (AML) have not demonstrated improvement in OS. Allogeneic hematopoietic stem cell transplant (HSCT) remains the only curative therapy but is associated with significant morbidity and mortality and infrequently utilized in clinical practice. Therefore, an urgent unmet need persists for effective therapies in this advanced phase patient population. Here, we review the current management and future directions of therapy in MPN-AP/BP.

The effects of free Cys residues on the structure, activity, and tetrameric stability of mammalian uricase

Mammalian uricases contain four conserved cysteine (Cys) residues, but little is known about their structures and functions. In this study, we first confirmed that all four Cys residues are free and not involved in disulfide bond formation, using canine uricase as a model protein. Cys residues had a greater effect on stability than on activity based on single Cys-to-Ser (serine) substitutions. Circular dichroism (CD) and homology modeling indicated that C188S reduces β-sheet contents and inter- and intra-subunit hydrophobic interaction, potentially impairing the core tetrameric β-barrel structure of the tunneling-fold protein, and ultimately decreased the tetrameric stability. Additionally, the inactivation of C188S during the stability tests may be a complex process involving depolymerization followed by irregular aggregation. Double mutations or thiol blockage of Cys188 and Cys195 significantly disrupted the formation and stability of tetrameric uricase, which may be mediated by the free thiols in Cys residues. The present results demonstrated that the free Cys residues are essential for tetrameric formation and stability in mammalian uricase. This implies that free cysteine residues, although not involved in disulfide bonding, may play important structural roles in certain proteins, underscoring the significance of the hydrophobic characteristics of the free thiols in Cys residues. KEY POINTS: • Four Cys residues are not involved in disulfide bonding in mammalian uricase. • The hydrophobicity of free thiols is critical for tetrameric stability in uricase. • Free Cys residues can serve structural roles without involving in disulfide bonds.

Butein inhibits cancer cell growth by rescuing the wild-type thermal stability of mutant p53

p53 is a transcription factor that activates the expression of various genes involved in the maintenance of genomic stability, and more than 50% of cancers harbor inactivating p53 mutations, which are indicative of highly aggressive cancer and poor prognosis. Pharmacological targeting of mutant p53 to restore the wild-type p53 tumor-suppressing function is a promising strategy for cancer therapy. In this study, we identified a small molecule, Butein, that reactivates mutant p53 activity in tumor cells harboring the R175H or R273H mutation. Butein restored wild-type-like conformation and DNA-binding ability in HT29 and SK-BR-3 cells harboring mutant p53-R175H and mutant p53-R273H, respectively. Moreover, Butein enabled the transactivation of p53 target genes and decreased the interactions of Hsp90 with mutant p53-R175H and mutant p53-R273H proteins, while Hsp90 overexpression reversed targeted p53 gene activation. In addition, Butein induced thermal stabilization of wild-type p53, mutant p53-R273H and mutant p53-R175H, as determined via CETSA. From docking study, we further proved that Butein binding to p53 stabilized the DNA-binding loop-sheet-helix motif of mutant p53-R175H and regulated its DNA-binding activity via an allosteric mechanism, conferring wild-type-like the DNA-binding activity of mutant p53. Collectively, the data suggest that Butein is a potential antitumor agent that restores p53 function in cancers harboring mutant p53-R273H or mutant p53-R175H. SIGNIFICANCE: Butein restores the ability of mutant p53 to bind DNA by reversing its transition to the Loop3 (L3) state, endows p53 mutants with thermal stability and re-establishes their transcriptional activity to induce cancer cell death.

Small-molecule correctors and stabilizers to target p53

The tumor suppressor p53 is the most frequently mutated protein in human cancer and tops the list of high-value precision oncology targets. p53 prevents initiation and progression of cancer by inducing cell-cycle arrest and various forms of cell death. Tumors have thus evolved ways to inactivate p53, mainly by TP53 mutations or by hyperactive p53 degradation. This review focuses on two types of p53 targeting compounds, MDM2 antagonists and mutant p53 correctors. MDM2 inhibitors prevent p53 protein degradation, while correctors restore tumor suppressor activity of p53 mutants by enhancing thermodynamic stability. Herein we explore both novel and repurposed p53 targeting compounds, discuss their mode of action, and examine the challenges in advancing them to the clinic.

Ferroptosis in acute leukemia

ABSTRACT

Ferroptosis is an iron-dependent cell death pathway that is different from apoptosis, pyroptosis, and necrosis. The main characteristics of ferroptosis are the Fenton reaction mediated by intracellular free divalent iron ions, lipid peroxidation of cell membrane lipids, and inhibition of the anti-lipid peroxidation activity of intracellular glutathione peroxidase 4 (GPX4). Recent studies have shown that ferroptosis can be involved in the pathological processes of many disorders, such as ischemia-reperfusion injury, nervous system diseases, and blood diseases. However, the specific mechanisms by which ferroptosis participates in the occurrence and development of acute leukemia still need to be more fully and deeply studied. This article reviews the characteristics of ferroptosis and the regulatory mechanisms promoting or inhibiting ferroptosis. More importantly, it further discusses the role of ferroptosis in acute leukemia and predicts a change in treatment strategy brought about by increased knowledge of the role of ferroptosis in acute leukemia.

atm Mutation and Oxidative Stress Enhance the Pre-Cancerous Effects of UHRF1 Overexpression in Zebrafish Livers

The ataxia-telangiectasia mutated (atm) gene is activated in response to genotoxic stress and leads to activation of the tp53 tumor suppressor gene which induces either senescence or apoptosis as tumor suppressive mechanisms. Atm also serves non-canonical functions in the response to oxidative stress and chromatin reorganization. We previously reported that overexpression of the epigenetic regulator and oncogene Ubiquitin Like with PHD and Ring Finger Domains 1 (UHRF1) in zebrafish hepatocytes resulted in tp53-dependent hepatocyte senescence, a small liver and larval lethality. We investigated the role of atm on UHRF1-mediated phenotypes by generating zebrafish atm mutants. atm^-/- adults were viable but had reduction in fertility. Embryos developed normally but were protected from lethality caused by etoposide or H₂O₂ exposure and failed to fully upregulate Tp53 targets or oxidative stress response genes in response to these treatments. In contrast to the finding that Tp53 prevents the small liver phenotype caused by UHRF1 overexpression, atm mutation and exposure to H₂O₂ further reduced the liver size in UHRF1 overexpressing larvae whereas treatment with the antioxidant N-acetyl cysteine suppressed this phenotype. We conclude that UHRF1 overexpression in hepatocytes causes oxidative stress, and that loss of atm further enhances this, triggering elimination of these precancerous cells, leading to a small liver.

TP53 Alterations in Myelodysplastic Syndromes and Acute Myeloid Leukemia

TP53 mutations are less frequent in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) than in solid tumors, except in secondary and therapy-related MDS/AMLs, and in cases with complex monosomal karyotype. As in solid tumors, missense mutations predominate, with the same hotspot mutated codons (particularly codons 175, 248, 273). As TP53-mutated MDS/AMLs are generally associated with complex chromosomal abnormalities, it is not always clear when TP53 mutations occur in the pathophysiological process. It is also uncertain in these MDS/AML cases, which often have inactivation of both TP53 alleles, if the missense mutation is only deleterious through the absence of a functional p53 protein, or through a potential dominant-negative effect, or finally a gain-of-function effect of mutant p53, as demonstrated in some solid tumors. Understanding when TP53 mutations occur in the disease course and how they are deleterious would help to design new treatments for those patients who generally show poor response to all therapeutic approaches.

Eprenetapopt combined with venetoclax and azacitidine in TP53-mutated acute myeloid leukaemia: a phase 1, dose-finding and expansion study

BACKGROUND

TP53-mutated acute myeloid leukaemia is associated with poor outcomes. Eprenetapopt (APR-246) is a first-in-class, small-molecule p53 reactivator. We aimed to evaluate the combination of eprenetapopt and venetoclax with or without azacitidine in patients with TP53-mutated acute myeloid leukaemia.

METHODS

This phase 1, multicentre, open-label, dose-finding and cohort expansion study was done at eight academic research hospitals in the USA. Inclusion criteria were age of at least 18 years; at least one pathogenic TP53 mutation; treatment-naive acute myeloid leukaemia according to the 2016 WHO classification; an ECOG performance status of 0-2; and a life expectancy of at least 12 weeks. In dose-finding cohort 1 patients received previous therapy with hypomethylating agents for myelodysplastic syndromes. In dose-finding cohort 2, previous use of hypomethylating agents was not permitted. Treatment cycles were 28 days. Patients in cohort 1 received intravenous eprenetapopt 4·5 g/day on days 1-4 and oral venetoclax 400 mg/day on days 1-28; those in cohort 2 also received subcutaneous or intravenous azacitidine 75 mg/m² on days 1-7. The expansion part of the study proceeded with patients enrolled as in cohort 2. Primary endpoints were safety in all cohorts (assessed in patients receiving at least one dose of assigned treatment) and complete response in the expansion cohort (assessed in patients who completed at least one treatment cycle and had at least one post-treatment clinical response assessment). The trial is registered with ClinicalTrials.gov, NCT04214860, and is complete.

FINDINGS

Between Jan 3, 2020, and July 22, 2021, 49 patients were enrolled across all cohorts. Six patients were initially enrolled into each of dose-finding cohorts 1 and 2; after no dose-limiting toxicities were observed, cohort 2 was expanded to enrol an additional 37 patients. The median age was 67 years (IQR 59-73). 24 (49%) of 49 patients were female and 25 (51%) male, and 40 (82%) were White. At data cutoff (Oct 1, 2021), the median length of follow-up was 9·5 months (IQR 6·1-11·5). No dose-limiting toxicities were recorded and the recommended phase 2 dose for eprenetapopt combinations was 4·5 g/day on days 1-4. Across all patients, adverse events of grade 3 or worse occurring in at least 20% of patients were febrile neutropenia (23 [47%] of 49 patients), thrombocytopenia (18 [37%] patients), leukopenia (12 [25%] patients), and anaemia (11 [22%] patients). Treatment-related serious adverse events occurred in 13 (27%) of 49 patients and there was one (2%) treatment-related death (sepsis). 25 (64%, 95% CI 47-79) of 39 patients had an overall response with eprenetapopt and venetoclax with azacytidine; 15 (38%, 23-55) had a complete response.

INTERPRETATION

Eprenetapopt and venetoclax with azacitidine had an acceptable safety profile and encouraging activity, supporting further frontline evaluation of this combination in the treatment of TP53-mutated acute myeloid leukaemia.

FUNDING

Aprea Therapeutics.

Case report: Sandwich therapy of CAR-T combined with ASCT: Sequential CAR-T cell therapy with ASCT after remission with CAR-T therapy caused long-term survival in a patient with relapsed/refractory Burkitt’s lymphoma with TP53 mutations

Burkitt’s lymphoma (BL) with TP53 mutation often has poor outcome after standard chemoimmunotherapy. Adoptive chimeric antigen receptor (CAR)-T cell therapy may be a new paradigm for treating refractory/relapsed (r/r) BL, but its therapeutic effects remain inconclusive. Here, we report a patient with r/r BL who failed to achieve complete remission (CR) and progressed rapidly after multiple protocol chemotherapy. The patient achieved CR with CAR19 and CAR22 T-cell cocktail therapy and obtained long-term disease-free survival after autologous hematopoietic stem cells (ASCT) and subsequential CAR19 and CAR22 T-cell cocktail therapy. The clinical evolution and genetic features of this case may provide some guidance for CAR-T therapy in overcoming relapses associated with TP53 gene mutations.

Gene Mutations and Targeted Therapies of Myeloid Sarcoma

OPINION STATEMENT

Myeloid sarcoma, a rare malignant tumor characterized by the invasion of extramedullary tissue by immature myeloid cells, commonly occurs concomitantly with acute myeloid leukemia, myelodysplastic syndromes, or myeloproliferative neoplasms. The rarity of myeloid sarcoma poses challenges for diagnosis and treatment. Currently, treatments for myeloid sarcoma remain controversial and primarily follow protocols for acute myeloid leukemia, such as chemotherapy utilizing multi-agent regimens, in addition to radiation therapy and/or surgery. The advancements in next-generation sequencing technology have led to significant progress in the field of molecular genetics, resulting in the identification of both diagnostic and therapeutic targets. The application of targeted therapeutics, such as FMS-like tyrosine kinase 3(FLT3) inhibitors, isocitrate dehydrogenases(IDH) inhibitors, and the B cell lymphoma 2(BCL2) inhibitors, has facilitated the gradual transformation of traditional chemotherapy into targeted precision therapy for acute myeloid leukemia. However, the field of targeted therapy for myeloid sarcoma is relatively under-investigated and not well-described. In this review, we comprehensively summarize the molecular genetic characteristics of myeloid sarcoma and the current application of targeted therapeutics.

Understanding the Continuum between High-Risk Myelodysplastic Syndrome and Acute Myeloid Leukemia

Myelodysplastic syndrome (MDS) is a clonal hematopoietic neoplasm characterized by bone marrow dysplasia, failure of hematopoiesis and variable risk of progression to acute myeloid leukemia (AML). Recent large-scale studies have demonstrated that distinct molecular abnormalities detected at earlier stages of MDS alter disease biology and predict progression to AML. Consistently, various studies analyzing these diseases at the single-cell level have identified specific patterns of progression strongly associated with genomic alterations. These pre-clinical results have solidified the conclusion that high-risk MDS and AML arising from MDS or AML with MDS-related changes (AML-MRC) represent a continuum of the same disease. AML-MRC is distinguished from de novo AML by the presence of certain chromosomal abnormalities, such as deletion of 5q, 7/7q, 20q and complex karyotype and somatic mutations, which are also present in MDS and carry crucial prognostic implications. Recent changes in the classification and prognostication of MDS and AML by the International Consensus Classification (ICC) and the World Health Organization (WHO) reflect these advances. Finally, a better understanding of the biology of high-risk MDS and the mechanisms of disease progression have led to the introduction of novel therapeutic approaches, such as the addition of venetoclax to hypomethylating agents and, more recently, triplet therapies and agents targeting specific mutations, including FLT3 and IDH1/2. In this review, we analyze the pre-clinical data supporting that high-risk MDS and AML-MRC share the same genetic abnormalities and represent a continuum, describe the recent changes in the classification of these neoplasms and summarize the advances in the management of patients with these neoplasms.

Targeted Therapy Development in Acute Myeloid Leukemia

Therapeutic developments targeting acute myeloid leukemia (AML) have been in the pipeline for five decades and have recently resulted in the approval of multiple targeted therapies. However, there remains an unmet need for molecular treatments that can deliver long-term remissions and cure for this heterogeneous disease. Previously, a wide range of small molecule drugs were developed to target sub-types of AML, mainly in the relapsed and refractory setting; however, drug resistance has derailed the long-term efficacy of these as monotherapies. Recently, the small molecule venetoclax was introduced in combination with azacitidine, which has improved the response rates and the overall survival in older adults with AML compared to those of chemotherapy. However, this regimen is still limited by cytotoxicity and is not curative. Therefore, there is high demand for therapies that target specific abnormalities in AML while sparing normal cells and eliminating leukemia-initiating cells. Despite this, the urgent need to develop these therapies has been hampered by the complexities of this heterogeneous disease, spurring the development of innovative therapies that target different mechanisms of leukemogenesis. This review comprehensively addresses the development of novel targeted therapies and the translational perspective for acute myeloid leukemia, including the development of selective and non-selective drugs.

50 years on and still very much alive: 'Apoptosis: a basic biological phenomenon with wide-ranging implications in tissue kinetics'

Cell death is part of the lifecycle of every multicellular organism. Nineteenth-century pathologists already recognised that organised forms of cell death must exist to explain the demise and turnover of cells during metamorphosis (of insects), embryogenesis and normal tissue homoeostasis [1]. Nevertheless, Kerr, Wyllie and Currie in their seminal paper of 1972, were the first to collate and define the distinct morphological features of controlled cell death in different contexts [2]. To describe the processes of cell deletion observed under both physiological and pathological conditions, they coined the term 'Apoptosis' (derived from the Greek word 'ἀπόπτωσις', meaning 'dropping off or falling off' of petals from flowers). Kerr, Wyllie and Currie defined apoptosis as a mechanism 'complementary to mitosis in the regulation of animal cell populations'. In addition, they already recognised the potential to use this programmed form of cell death for cancer therapy, but they also emphasised the occurrence of apoptosis during cancer development. In this article, some 50 years after its initial publication in The British Journal of Cancer, we revaluate and put the authors initial assumptions and general concepts about apoptosis into the context of modern-day biology.

TP53 signal pathway confers potential therapy target in acute myeloid leukemia

TP53 mutation is a frequent tumor suppressor mutation and a critical prognostic indicator across studies in many malignant tumors including hematologic malignancies. However, the role of TP53 and its correlative pathway in acute myeloid leukemia (AML) is enigmatic, which may provide possible emerging strategies with the potential to improve outcomes in AML. Accordingly, we focus not only on the TP53 mutation but also on the underlying mechanisms of the mutated TP53 signal pathway. While it is now generally accepted that TP53 mutations are widely associated with a dismal prognosis, resistance to chemotherapy, and high incidence of relapse and refractory AML. Hereby, the current therapeutics targeting TP53 mutant AML are summarized in this review. This will address emerging TP53-based therapeutic approaches, facilizing the TP53-targeted treatment options.